On the FreeBSD boxes I maintain I see a lot of cruft piling up in /var/db/portsnap/files. How to get rid of this? From former experience that just removing these snapshot files is a bad idea, it breaks portsnap. I've seen a suggestion on the web to remove /var/db/portsnap and the ports tree alltogether, and redownload everything with portsnap fetch extract, but that appears to be overkill to me. What do you suggest to keep the portsnap directory clean?